Important!

If the circuit pack to be replaced is the active circuit pack for timing and the circuit pack is removed, the system performs an automatic protection switch and subsequent transmission hits (less than 60 ms) will occur. If desired, perform this step to determine the timing state of the circuit pack to be replaced.

Select View → Timing/Sync. Observe the value of the Active Circuit Pack parameter to determine the active circuit pack for timing. Click Close.

Important!

If the circuit pack to be replaced is the active circuit pack for timing, an optional manual timing switch can be performed before replacing the circuit pack. Transmission hits (less than 60 ms) will occur for each separate protection switch.

If the circuit pack to be replaced is not the active circuit pack for timing, proceed to Step 4.

To perform an optional manual timing switch, select Fault → Timing/Sync Protection Switch → Main Circuit Pack Timing Switch. Select the Manual Switch Command and click OK.

Result:

A dialog box appears asking you to confirm executing this command. Click Yes.

If required, repeat Step 1 to verify that the circuit pack to be replaced is not the active circuit pack for timing.

Important!

If the circuit pack to be replaced is the active circuit pack for transmission and the circuit pack is removed, the system performs an automatic protection switch and subsequent transmission hits (less than 60 ms) will occur. If desired, perform this step to determine the transmission state of the circuit pack to be replaced.

Select View → Protection to access the required protection group (according to the work instructions) and determine if the circuit pack to be replaced is active for transmission. Record the active paths supported by the circuit pack to be replaced. Click Close.

Important!

If the circuit pack to be replaced is active for transmission, optional manual switches can be performed before replacing the circuit pack. Transmission hits (less than 60 ms) will occur for each separate protection switch.

If the circuit pack to be replaced is not active for transmission, proceed to Step 6.

To perform an optional manual transmission switch, select Fault → Protection Switch. Select the required 1+1 Line and click Select. Select the Manual Switch Type and click Apply.

Result:

A dialog box appears asking you to confirm executing this command. Click Yes.

The ABN LED is lighted on the SYSCTL circuit pack faceplate.

The system reports a manual switch condition for the affected line.

If required, repeat Step 4 to verify that the circuit pack to be replaced is not the active circuit pack for transmission.

STOP! To complete the upgrade, return to the procedure that directed you to perform this procedure.

End of steps